Slice hoagie rolls 3/4 of the way through so that both sides of the rolls are still attached. Spread the softened butter over both sides of the rolls. Heat a large pan over medium heat. Place the rolls buttered side down into the pan, gently press down and toast until golden brown, about 1 minute or less. Set toasted rolls aside.
Heat 1 tablespoon oil in a large pan or skillet over medium high heat. Add in the onions and bell peppers and season with 1/2 teaspoon each of salt and black pepper, adjust to taste. Cook the veggies, stirring intermittently, until mostly cooked but not fork tender, about 4-5 minutes. Transfer veggies to a plate and set aside. (If veggies start to dry out during cooking process, add in a few splashed of water, as needed.)
In the same pan used to cook the veggies, heat up the remaining 1 tablespoon of oil. Add in the steak, Worcestershire sauce, garlic powder, and the remaining salt and black pepper (adjust to taste). Cook steak, stirring intermittently, until it is no longer pink, fully browned and all released liquid is cooked out, 5 to 6 minutes or longer as needed. (If steak renders off a lot of fat during cooking process, use a paper towel to soak up any excess oil.)
Add the veggies and mozzarella cheese into the pan with the cooked steak and mix in to combine. Reduce heat to medium low. Divide the mixture into (2) portions that is the length of the rolls. Layer (2) slices of provolone cheese over each portion and cover the pan with a lid to melt the cheese.
In a small dish, mix together the mayonnaise and grated garlic. Spread a thin layer of the garlic mayo on both sides of the rolls.
Use a spatula to scoop and add the divided portions into each roll.
Serve Philly cheesesteaks while still hot on its own or with a side of heated cheese sauce and fries (optional). Enjoy!